Hello, I don't know currently if the mainboard here is the problem but it seems the most likely option. Whenever I start playing audio there is a slight chance that I will hear like a popping sound on one of my headphones sides (happens on both though). This is kind of like a jumpscare to me so I really can't keep it like it is. No crackling/popping to hear when audio is running, just the start/stop of audio playback creates this problem.
Is there anything I can try to stop this/find the cause or maybe contact ASUS support directly? I am guessing the USB Port driver has an issue.
By the way this is by using a USB DAC unit, the same I used in my old setup which never had this problem.
Edit: Seems like the problem was actually the USB soundcard in my case. I had another one laying around and the issue has gone away. After I plugged the soundcard into my old setup there was also crackling there so I am guessing it somehow broke the same moment I got my new setup. Maybe plugging it out after a year of it not moving destroyed some contact inside of the cable, who knows.
